Les Baer does just what you are talking about. Click on the link below, and look at the 3rd picture down, the “Home Defense” pistol. Also note the frame is reinforced, and does not taper down as it gets closer to the end of the barrel, like every other 1911. I would think there is a reason for this. (Side note, the non-tapering frame also means that it will NOT fit a regular 1911 kydex holster)
My question is, why would you want to drill a frame, when there are so many lights that you can attach to the front of the trigger guard, that would basically be in the same location as a rail mounted one?